Welcome to the community.
No - your iPad cannot directly make cellular calls over a cellular network. However...
Depending upon your carrier, your iPad’s WiFi Calling feature is not necessarily dependent upon proximity of your iPhone. Whilst it is true that your iPad can make/relay calls via your iPhone, many Cellular Carriers that support full WiFi Calling features allow your iPad to make calls (over any WiFi connection) independently of your iPhone. Calls can be made or received when the iPhone is either OFF or elsewhere entirely; calls are, however, billed to your cellular account.
When this feature is activated on your iPad (subject to Carrier support) as shown above, you effectively have a second phone line. To all intents and purposes, other than not routing the call over the cellular network, you have a separate telephone line on your iPad that’s independent of your iPhone - but shares its billing.
Check for full WiFi Calling support, for iPad, with your Cellular Carrier.
I hope you find this helpful.